Most single-driver speakers and electrostatics will image very very well, not only on vocals, but on everything else also. As was stated above, the upstream components are very important to this.
Speakers that have holographic imaging on vocals..
As far as 3-d imaging on vocals...I found only a handful...namely Spendors,Vandersteens,and older Spica tc-50s that I used to own capable of doing this...and this includes auditioning Maggies,Thiels,Revels,Logans, and too many more to mention...any thoughts?